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UNITED STATES PATENT OFICE.

GERALD I-I. ALLEN AND WILLIAM H. ALLEN, OF DETROIT, MICHIGAN; SAIDGERALD H. ALLEN ASSIGNOR TO SAID WILLIAM H. ALLEN.

RUST-PREVENTING COATING.

No Drawing.

T 0 all whom it may concern:

Be it known that we, GERALD H. ALLEN and YVILLIAM H. ALLEN, citizens ofthe United States, and residents of Detroit, in the county of l/Vayneand State of Michigan, have invented a new and Improved Rust- PreventinCoating, of which the following is a speei cation.

This invention relates to the art of preventing therusting of surfacesof iron and steel containing sulfur in combination, by coating thesesurfaces with an unstable chemical which will cause the oxids of sulfur,formed by the oxidation of said sulfur in combination with the iron, tocombine, as rapidly as the oxids are formed, with the coating chemicaland convert said oxids into stable inactive compounds.

Compounds of silicon and iron, phosphorus and iron, and manganese andiron, marketed under the names of ferro-silicon, ferro-phosphorus andterm-manganese, do not oxidize when wetted and exposed to the air to anyappreciable extent, while ferrous sulfids rapidly turn red through theoxidation of the iron when so treated.

1f normally insoluble barium phosphates, Ba.,(Po,),, BaHPO and water bebrought in contact with ferrous sultid. the latter does not turn redthrough the oxidation of the Specification of Letters Patent.

Application filed February 20, 1918.

Patented June 3, 1919.

serial No. 218,364.

as these would interfere with the ionization of the phosphates whenWetted with rain water or condensed moisture, but we employ a vehicle.which will permit the passage of water through the coating of bariumphosphate and yet have sufficient adhesive properties to hold thephosphates against the surface of the metal. The preferred vehicles arecasein, glue, silicate of soda, and barium hydrate although any otheradherent vehicle of the same general character which is inert to themetal may be employed. T he ground barium phosphate is mixed with thevehicle to the consistency of a thin paint and either 5 brushed, sprayedor otherwise applied to the surface to be treated. The metallic radicalin the barium phosphates may be replaced by any other metal whosesulfates are insoluble or substantially insoluble in water, par- 6t-icularly strontium or lead, but these two do not function as well asbarium.

\Ve claim v 1. A coating for protecting surfaces of iron and steelcomprising an adherent vehi- 6 cle which is inert to the metal capableof absorbing water and barium phosphate.

2. A coating for protecting surfaces of iron and steehcomprising anadherent vehicle which is inert to the metal capable of absorbing waterand the phosphate of a metal whose sulfate is insoluble in water.

3. A coating for protecting surfaces of iron and steel comprising caseinand barium phosphate.

4:. A coating for protecting surfaces of iron and 'steel comprisingcasein and the phosphate of a metal whose sulfate is insoluble in Water.J

i o. H. ALLEN.

WILLIAM H. ALLEN.

